Tchanguiz Razban

Study of a matching circuit effect on a microwave rectifier

An effective method is proposed to design a matching circuit for a microwave rectifier in order to manage the frequency bandwidth and the power bandwidth. Although the input impedance is affected by the nonlinear behavior of diodes with the variation of input power levels, the analysis on a variety of matching circuit configuration brings more evidence to improve the performance of rectifiers. This method has been applied in a low cost, zero-bias Schottky diode rectifier having RF-DC conversion efficiency of 55 %. The nonlinear simulation of rectifier circuit and an analytic description of multiple dimensional parameters are the key to study the relation between the nonlinear performance of a rectifier and its matching circuit.

Schottky diode rectifier for power harvesting application

This paper presents a study of rectifier prototype and diode modelization. The rectifying circuit with single Schottky diode HSMS-2860 at 2.45 GHz is proposed for energy harvesting applications. In such applications, the input power is very low, mainly about -20 dBm. Based on an analysis of matching circuit, the rectifiers with single stub matching circuit, with radial stubs low pass filter, or with compact structure were designed by using circuit simulation and co-simulation in ADS. The output DC voltages of 36.2 mV and the conversion efficiency of 1.3% were measured over a load resistance of 10 kΩ for -20 dBm microwave incident power.

A new design of an S/X dual band circular slot antenna for radar applications

Abstract A novel design of dual-band slot antenna with a circular patch for radar applications is presented and studied. It is fed by a micro-strip line and built on a FR-4 substrate with a whole size of 18 X 30 mm2. A dual band printed antenna is created by introducing slots on the radiating element. By this, two bandwidth, covering C and X band, are achieved. In order to obtain a good fundamental antenna design, the initial studies were carried out theoretically, using CST Microwave Studio simulation software. In this case, the frequency range at return loss <10 dB is 5.24–6.16 GHz for low frequency and is 7.9–11.7 GHz for high frequency. In addition, the proposed antenna has good radiation characteristics and stable gains over the whole operating bands. A prototype of antenna is fabricated and tested. Experimental data show good agreement between simulated and measured results.

Design of electrically tunable phase shifter for antenna arrays operating in Ku-band

This paper deals with the modeling and simulation of a wideband analog phase shifter for Ku applications. The structure adopted is based on a 90° branch-line coupler loaded by varactor diodes used to provide a wide phase shift range. The main idea of this work is to integrate controlled phase shifters in the antenna array in order to control its main beam between different satellites. Several circuits have been tested and optimized using ADS software from Agilent Technologies to obtain a wide bandwidth and wide phase shift range with low insertion loss over the Ku band.

Bandwidth enhancement of microstrip antenna with circular slot for Ku-band satellite applications

This paper addresses the design and development of a broadband antenna for Ku-band satellite applications. It introduces a technique in order to put up the final structure of the proposed antenna. A relative bandwidth of 30%, from 11.6GHz to 14.8GHz, is obtained for a footprint of less than 13.13mm × 8.86mm. Good agreement between simulation and measurement results show the interest of this approach.

A Simple Method to Stabilize Radiation Pattern over a Large Bandwidth

An alternative radiation stabilization method has been presented for patch antenna. With this method, side radiation could be suppressed when a conductor ring and a circular slot both with the width of a quarter-wavelength are placed on the same layer and around patch antenna. An experimental structure has been simulated and the distance from antenna part to conductor ring is optimized using parametric function of HFSS software. Measured results given in this paper obviously indicate that not only the side radiation from the boundary of substrate could be suppressed effectively, but also the antenna directivity could be adjusted and enhanced after this method has been carried out. Both simulation and measurement indicate that when the distance is set to one guided wavelength (), side radiation could be suppressed the most effectively and the return loss of patch antenna is only slightly affected.

Design of a Wideband and Dual-Polarized CPW-Fed Monopole Antenna for Future 5G Communications

As fast development in communication field, sub-6 GHz spectrum band becomes ultra crowd. Even though Carrier Aggregation (CA) and higher order modulation used, available spectrum is still the bottleneck of communication speed and network latency. Nowadays, more and more companies and institutes are paying more attention to over 6GHz communication system research. Recently released news indicate frequency points are mainly on 12GHz, 15GHz, 28GHz, 38GHz even 70GHz, and accompanied working bandwidth is about 400MHz to 1GHz. As working band goes higher, antenna conceptions will also be updated. A CPW-Fed monopole antenna working in KU-band with more than 20% relative bandwidth is hereby introduced, which might be a good candidate for future 5G cellular networks and also satellite based DBS reception system. Proposed antenna has small profile lower than &#955;g /4 with dual-polarization, which is thus suitable for base station and mobile device conceptions.

Compact tunable Ku-band Schiffman phase shifter for beam-steering applications

This study focuses on the design of a tunable compact phase shifter intended for Ku applications. The adopted topology is based on the basic Schiffman model where the coupled microstrip transmission lines have been modified and loaded by Varactor diodes. Various models of phase shifters can be obtained by moving the location of these diodes and optimized using ADS software from Agilent Technologies. The modified Schiffman phase shifter is able to create a continuously tunable phase shift by varying the voltage of the diodes while ensuring good performance over the entire operating band.

Circular polarization rectangular Dielectric Resonator Antenna for UHF RFID applications

A low profile circularly polarized RFID (radio frequency identification) reader antenna is designed and analysed for operation at the European ultra-high frequency (UHF) band, ranging from 865-868 MHz. The proposed Dielectric Resonator Antenna (DRA) is composed of microstrip line/slot feed and a rectangular dielectric resonator made from a high-permittivity (εr = 30). The simulated results show satisfactory performance versus size. The antenna works from 857 to 885 MHz, thus covering the European UHF RFID Band, and its circularly polarized radiation pattern provides a 3.75 dBi realized gain.

Characterization of electrooptic polymer applied to microwave sensing

In this paper we present electrooptic measurement of a crosslinked side chain PGMA/DR1 polymer. Measured values are as high as 11 pm/V at 1310 nm, we present measurement as a function of incident beam reflexion point and show dependance between the reflexion point location over the sample and the measured electrooptic coefficient. We present low frequency relative dielectric constant using a capacitance measurement method. Using this method, we found a relative permittivity of 4.46plusmn0.38 for our polymer. We present a new electrooptic microwave sensor, where we enhance the electrooptical interaction by increasing the optical path length using a Fabry-Perot cavity and we concentrate the electric field inside our device using a microstrip resonator. Expected interaction enhancement value is expected to be as high 310deg compared to the simple reflexion case at low frequency